Exhaust adapter

ABSTRACT

An exhaust adapter includes a cylindrical part for connecting an exhaust pipe of a combustion device to a collective exhaust duct; and a backflow prevention structure for preventing backflow of the exhaust from the collective exhaust duct side to the exhaust pipe side. The backflow prevention structure includes: a damper receiving part formed with an opening through which the exhaust from the exhaust pipe passes; an exhaust damper plate that opens the opening by pressure of the exhaust from the exhaust pipe and closes the opening by its own weight when there is no exhaust from the exhaust pipe; a support shaft that rotatably supports the exhaust damper plate; and a bearing part that supports the support shaft. A pair of shaft hole parts of the exhaust damper plate for inserting the support shaft is formed in a long hole shape.

CROSS REFERENCE TO RELATED APPLICATIONS

The present invention claims priority under 35 U.S.C. § 119 to Japanese Application No. 2021-103864 filed on Jun. 23, 2021 the entire content of which is incorporated herein by reference.

BACKGROUND Technical Field

The disclosure relates to an exhaust adapter that connects exhaust pipes of multiple combustion devices and a collective exhaust duct, and more particularly to an exhaust adapter including a backflow prevention structure that prevents backflow of exhaust to the combustion devices.

Description of Related Art

Conventionally, for example, in a bathing facility or the like having multiple hot water taps, a hot water supply system configured by multiple hot water supply devices has been used. This hot water supply system supplies hot water by the number of operating units according to the amount of hot water supply. Each hot water supply device has a combustion device equipped with a blower fan that blows combustion air, and heats hot water using the combustion heat of the combustion device. The exhaust discharged from the exhaust pipe of the combustion device is collected in the collective exhaust duct and discharged to the outside collectively.

For the connection between the exhaust pipe of each combustion device and the collective exhaust duct, an exhaust adapter including a backflow prevention structure for preventing backflow of the exhaust from the collective exhaust duct to the combustion device is used. The backflow prevention structure is configured to close by its own weight when there is no exhaust from the combustion device and to open by the pressure of the exhaust of the combustion device. For example, as in Patent Literature 1, known is an exhaust adapter including a backflow suppression part corresponding to a backflow prevention structure configured by a lid-shaped member and a support mechanism thereof in a part formed thicker (having larger cross-sectional area) than the exhaust pipe.

RELATED ART Patent Literature

-   [Patent Literature 1] Japanese Patent Laid-open Publication No.     6767087

SUMMARY Technical Problem

In Patent Literature 1, the backflow suppression part in the middle part of the exhaust adapter is formed thicker than the connection part to the exhaust pipe and the collective exhaust duct, and in this widened space, a lid-shaped member that covers the outlet of the exhaust from the exhaust pipe and a support mechanism that rotatably supports the lid-shaped member are provided. However, since the backflow suppression part is thick, when the exhaust adapter is covered with a heat insulating member for safety, for example, it is not easy to attach the heat insulating member.

Further, in the backflow prevention structure, due to machining error and assembly error of the member, even if there is no exhaust from the combustion device, the lid-shaped member may not be able to close the outlet of the exhaust from the exhaust pipe, and a gap may be formed. Since the exhaust passes through this gap, the backflow prevention function deteriorates. Therefore, for example, as shown in FIG. 12 , in the backflow prevention structure in which an exhaust damper plate 31 corresponding to the lid-shaped member opens and closes an exhaust outlet 33 formed in a damper receiving part 32, a support shaft 34 is inserted into round holes of a pair of shaft insertion parts 31 a, and a pair of long holes 36 through which the support shaft 34 is inserted is formed in a bearing part 35. In this way, the exhaust damper plate 31 is allowed to move in the vertical direction within the range of the long holes 36, and the exhaust damper plate 31 is ensured to abut on the exhaust outlet 33 by its own weight.

However, since the support shaft 34 can move in the vertical direction together with the exhaust damper plate 31 within the range of the long holes 36, for example, the support shaft 34 may get stuck in an inclined posture, and the smooth rotation of the exhaust damper plate 31 is hindered, and the function of the backflow prevention structure may deteriorate or may fail to function.

The disclosure provides an exhaust adapter having a width equal to that of an exhaust pipe and including a backflow prevention structure capable of preventing a deterioration of the backflow prevention function.

Solution to Problem

An exhaust adapter according to a first aspect of the disclosure includes a cylindrical part for connecting an exhaust pipe of a combustion device to a collective exhaust duct for collecting and discharging exhaust of a plurality of the combustion devices; and a backflow prevention structure for preventing backflow of the exhaust from the collective exhaust duct side to the exhaust pipe side. The backflow prevention structure includes: a damper receiving part formed with an opening through which the exhaust from the exhaust pipe passes; an exhaust damper plate that opens the opening by pressure of the exhaust from the exhaust pipe and closes the opening by its own weight when there is no exhaust from the exhaust pipe; a support shaft that rotatably supports the exhaust damper plate; and a bearing part that supports the support shaft. The exhaust damper plate comprises a pair of shaft hole parts for inserting the support shaft, and the pair of shaft hole parts is formed in a long hole shape that is long in a vertical direction with respect to the support shaft when the exhaust damper plate is in a posture in which the opening is closed.

According to the above configuration, the exhaust adapter connects the exhaust pipe and the collective exhaust duct by the cylindrical part. In the backflow prevention structure of this exhaust adapter, the exhaust damper plate rotates due to the pressure of the exhaust from the exhaust pipe to open the opening of the damper receiving part, and when there is no exhaust from the exhaust pipe, the exhaust damper plate closes the opening by its own weight to prevent the backflow of the exhaust from the collective exhaust duct. The support shaft supported by the bearing part for rotatably supporting the exhaust damper plate is inserted into the pair of shaft hole parts provided in the exhaust damper plate. Since the support shaft is supported by the bearing part and does not incline, the rotation of the exhaust damper plate is not hindered by the inclination of the support shaft. The pair of shaft hole parts is formed in a long hole shape that is long in the vertical direction with respect to the support shaft when the exhaust damper plate is in a posture in which the opening is closed. Since the pair of shaft hole parts allows the exhaust damper plate to move in the vertical direction in a posture in which the opening is closed with respect to the support shaft, the exhaust damper plate can be made to abut on the damper receiving part so as to close the opening of the damper receiving part by its own weight. Therefore, it is possible to prevent the formation of a gap between the damper receiving part and the exhaust damper plate to prevent the backflow of the exhaust, and since the rotation of the exhaust damper plate is not hindered, it is possible to prevent the backflow prevention function from deteriorating.

In the exhaust adapter according to a second aspect of the disclosure, further to the first aspect of the disclosure, the cylindrical part is formed to have a width equal to a width of the exhaust pipe, and the damper receiving part has an outer shape that is formed in a circular shape along an inner circumference of the cylindrical part, and the opening is formed in a shape of a circle with a center eccentric from a center of the circular damper receiving part, or formed in a partial circular shape having a part of this circle.

According to the above configuration, since the damper receiving part has the outer shape that is formed in the shape of a circle along the inner circumference of the cylindrical part of the exhaust adapter, the exhaust adapter provided with the backflow prevention structure can be formed in the cylindrical part having the same width as the exhaust pipe. The opening through which the exhaust passes is formed in the shape of a circle with the center eccentric from the center of the circular damper receiving part, or formed in a partial circular shape having a part of this circle. The support shaft of the exhaust damper plate that opens and closes the opening and the bearing part thereof can be accommodated in the cylindrical part while increasing the opening area by the eccentric circular shape or partially circular shape of the opening.

In the exhaust adapter according to a third aspect of the disclosure, further to the second aspect of the disclosure, the bearing part is provided in a wide part of the damper receiving part formed by making the opening eccentric.

According to the above configuration, by making the opening eccentric with respect to the damper receiving part, the wide part is formed in the damper receiving part, and the bearing part is provided in the wide part. Therefore, since the bearing part of the support shaft that rotatably supports the exhaust damper plate is provided in the wide part outside the opening, the exhaust adapter having a constant width may be formed without expanding the diameter of the cylindrical part. Therefore, when the exhaust adapter is covered with the heat insulating material, it can be easily covered because there are no parts having different widths.

Effects

The disclosure provides an exhaust adapter having a width equal to that of an exhaust pipe and including a backflow prevention structure capable of preventing a deterioration of the backflow prevention function.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration view of a hot water supply system having multiple hot water supply devices.

FIG. 2 is a top view of an exhaust adapter connecting the exhaust pipe of the combustion device and the collective exhaust duct as viewed from the collective exhaust duct side.

FIG. 3 is a cross-sectional view taken along the line of FIG. 2 .

FIG. 4 is a perspective view of a backflow prevention structure mounted on the exhaust adapter.

FIG. 5 is an assembly illustration view of the backflow prevention structure.

FIG. 6 is a top view of the backflow prevention structure as viewed from the collective exhaust duct side.

FIG. 7 is a cross-sectional view taken along the line VII-VII of FIG. 6 .

FIG. 8 is a top view of another example of the backflow prevention structure as viewed from the collective exhaust duct side.

FIG. 9 is a cross-sectional view showing a state in which the backflow prevention structure of FIG. 6 has started to open.

FIG. 10 is an enlarged cross-sectional view of a main part for illustrating the start of opening of the backflow prevention structure of FIG. 9 .

FIG. 11 is a cross-sectional view showing a fully open state of the backflow prevention structure of FIG. 6 .

FIG. 12 is an illustration view of a support shaft and a bearing part of a conventional backflow prevention structure.

DESCRIPTION OF EMBODIMENTS

Hereinafter, modes for carrying out the disclosure will be described with reference to embodiments.

EMBODIMENT

First, a hot water supply system 1 will be described.

As shown in FIG. 1 , the hot water supply system 1 is configured by, for example, three hot water supply devices 11 a to 11 c as multiple hot water supply devices. The hot water supply devices 11 a to 11 c include corresponding combustion devices 3 a to 3 c. Exhaust pipes 4 a to 4 c extending upward from the combustion devices 3 a to 3 c are connected to a collective exhaust duct 2 above the hot water supply devices 11 a to 11 c via corresponding exhaust adapters 5 a to 5 c. Further, the exhaust adapters 5 a to 5 c may be connected to the exhaust pipes 4 a to 4 c and the collective exhaust duct 2, respectively, via, for example, a flexible duct, so as to be compatible with various sites (positional relationship between the exhaust pipes 4 a to 4 c and the collective exhaust duct 2).

For example, the hot water supply device 11 a has a blower fan 6 a which is a part for blowing air for combustion, and a burner 7 a for burning fuel. A heat exchanger 12 a for heating hot water by combustion heat is provided between the burner 7 a and the exhaust pipe 4 a. The hot water supply device 11 a has a control part 14 a, and the control part 14 a controls the drive of the blower fan 6 a and the combustion of the burner 7 a to supply hot water heated to a predetermined temperature.

Similar to the hot water supply device 11 a, the other hot water supply devices 11 b and 11 c include blower fans 6 b and 6 c, burners 7 b and 7 c, heat exchangers 12 b and 12 c, control parts 14 b and 14 c, and the like. The hot water supply system 1 has a control unit 16 for hot water supply operation that supplies hot water by the number of operating hot water supply devices according to the amount of hot water supply, and an operation terminal 17 connected to the control part 16. In FIG. 1 , the hot water supply devices 11 b and 11 c are performing hot water supply operation.

The collective exhaust duct 2 collects the exhaust from the hot water supply system 1 configured by the multiple hot water supply devices 11 a to 11 c and discharges the exhaust to the outside collectively. The exhaust adapter 5 a includes a backflow prevention structure 18 a that prevents the exhaust of the other combustion devices 3 b and 3 c from flowing back through the collective exhaust duct 2 during non-combustion of the connected combustion device 3 a. The backflow prevention structure 18 a opens by the pressure of the exhaust of the combustion device 3 a and closes by its own weight when there is no exhaust of the combustion device 3 a to prevent the backflow of the exhaust. The exhaust adapters 5 b and 5 c are equipped with the same backflow prevention structures 18 b and 18 c.

Hereinafter, the exhaust adapter 5 a provided with the backflow prevention structure 18 a will be described, and the description of the exhaust adapters 5 b and 5 c having the same configuration will be omitted.

As shown in FIGS. 1 to 3 , the exhaust adapter 5 a has a cylindrical part 21 for connecting the exhaust pipe 4 a extending upward from the combustion device 3 a and the collective exhaust duct 2, and the backflow prevention structure 18 a for preventing backflow of the exhaust from the collective exhaust duct 2 side to the exhaust pipe 4 a side. The cylindrical part 21 is formed to have a predetermined width equal to that of the exhaust pipe 4 a. The backflow prevention structure 18 a is provided to close the inside of the cylindrical part 21.

As shown in FIGS. 4 to 7 , the backflow prevention structure 18 a is configured by an exhaust damper plate 22, a damper receiving part 23, a support shaft 24, and a bearing part 25. The damper receiving part 23 having a circular outer shape formed along the inner circumference of the cylindrical part 21 is formed with a circular opening 26 through which the exhaust from the exhaust pipe 4 a passes. The center C1 of the opening 26 is eccentric with respect to the center C0 of the circular damper receiving part 23. The bearing part 25 is joined to a wide part 23 a of the damper receiving part 23 formed by making the opening 26 eccentric to match a pair of positioning protrusions 23 b.

The bearing part 25 has a pair of round holes 25 a parallel to the damper receiving part 23 for inserting the support shaft 24 in a direction orthogonal to the straight line connecting the center C1 of the opening 26 and the center C0 of the damper receiving part 23. In the support shaft 24 inserted through the bearing part 25, the movement in the direction orthogonal to the shaft is restricted by the bearing part 25, and the movement in the shaft direction is restricted by deforming both ends of the support shaft 24 or attaching a cap member. As a result, the bearing part 25 supports the support shaft 24 so as not to move.

The opening 26 is formed inside a cylindrical wall part 23 c that protrudes upward (on the collective exhaust duct side) from the damper receiving part 23, and the tip part of the cylindrical wall part 23 c is bent inward. The exhaust damper plate 22 formed in a circular shape larger than the opening 26 for closing the opening 26 has a rectangular extension part 22 a extending radially outward. A shaft insertion part 22 b having a semi-circular part is formed to extend upward from both ends of the extension part 22 a parallel to the radial direction in which the extension part 22 a extends.

The shaft insertion part 22 b has a pair of shaft hole parts 22 c for inserting the support shaft 24. The pair of shaft hole parts 22 c is formed in a long hole shape that is long in the vertical direction with respect to the inserted support shaft 24 when the exhaust damper plate 22 is in a posture in which the opening 26 is closed. As a result, the exhaust damper plate 22 is allowed to move in the vertical direction with respect to the support shaft 24 fixed to the damper receiving part 23 via the bearing part 25. Therefore, the machining error and the assembly error of the backflow prevention structure 18 a are absorbed by the shaft hole parts 22 c in a long hole shape, and the exhaust damper plate 22 easily abuts on the tip part of the cylindrical wall part 23 c by its own weight.

As shown in FIG. 8 , for example, in order to increase the opening area, the opening 26 may be formed in a partial circular shape (D shape) having a part of the circle with the center C1 eccentric with respect to the center C0 of the damper receiving part 23. In this case, the exhaust damper plate 22 is formed in a shape that can close the opening 26.

When the exhaust from the combustion device 3 a passes through the exhaust adapter 5 a and flows into the collective exhaust duct 2, the exhaust damper plate 22 is pushed up by the pressure of the exhaust as shown in FIG. 9 , and the backflow prevention structure 18 a starts to open. At this time, as shown in FIG. 10 , the exhaust damper plate 22 starts to rotate so as to open the opening 26 with the tip part of the cylindrical wall part 23 c as a fulcrum on the support shaft 24 side, and the extension part 22 a and the shaft insertion part 22 b are lowered. Since the shaft hole parts 22 c have a long hole shape, the extension part 22 a and the shaft insertion part 22 b are lowered until the backflow prevention structure 18 a is opened to some extent and the upper edge parts of the shaft hole parts 22 c abut on the support shaft 24. As a result, even when the pressure of the exhaust is not strong, the weight of the exhaust damper plate 22 pushed up by the exhaust when the backflow prevention structure 18 a in the closed state is opened is reduced, so that the backflow prevention structure 18 a can be easily opened. When the upper edge parts of the shaft hole parts 22 c abut on the support shaft 24, the exhaust damper plate 22 including the extension part 22 a and the shaft insertion part 22 b rotates around the support shaft 24, and the backflow prevention structure 18 a opens to a greater extent.

As shown in FIG. 11 , the bearing part 25 is equipped with a rotation restricting part 25 b that receives the rotation of the exhaust damper plate 22 at a predetermined position. The rotation restricting part 25 b prevents the backflow prevention structure 18 a from opening too much due to the pressure of the exhaust and not being closed by the weight of the exhaust damper plate 22. When the exhaust is stopped, the exhaust damper plate 22 rotates by its own weight and abuts on the tip part of the cylindrical wall part 23 c, and the exhaust damper plate 22 closes the opening 26. The closed backflow prevention structure 18 a prevents the exhaust of the other combustion devices 3 b and 3 c from flowing back through the collective exhaust duct 2 (see FIG. 1 ).

The operation and effect of the exhaust adapter 5 a provided with the backflow prevention structure 18 a will be described.

The exhaust adapter 5 a connects the exhaust pipe 4 a of the combustion device 3 a to the collective exhaust duct 2. The backflow prevention structure 18 a of the exhaust adapter 5 a opens the opening 26 formed in the damper receiving part 23 by rotating the exhaust damper plate 22 by the pressure of the exhaust from the exhaust pipe 4 a. On the other hand, when there is no exhaust from the exhaust pipe 4 a, the exhaust damper plate 22 closes the opening 26 by its own weight to prevent the backflow of the exhaust from the collective exhaust duct 2.

The support shaft 24 supported by the bearing part 25 for rotatably supporting the exhaust damper plate 22 is inserted into the pair of shaft hole parts 22 c provided in the exhaust damper plate 22. Since the support shaft 24 is supported by the bearing part 25 and does not incline, the rotation of the exhaust damper plate 22 is not hindered by the inclination of the support shaft 24.

The pair of shaft hole parts 22 c is formed in a long hole shape that is long in the vertical direction with respect to the support shaft 24 when the exhaust damper plate 22 is in a posture in which the opening 26 is closed. Since the pair of shaft hole parts 22 c allows the exhaust damper plate 22 to move in the vertical direction in a posture in which the opening 26 is closed with respect to the support shaft 24, the exhaust damper plate 22 can be made to abut on the damper receiving part 23 so as to close the opening 26 of the damper receiving part 23 by its own weight. Therefore, it is possible to prevent the formation of a gap between the damper receiving part 23 and the exhaust damper plate 22 to prevent the backflow of the exhaust, and since the rotation of the exhaust damper plate 22 is not hindered, it is possible to prevent the backflow prevention function from deteriorating.

Since the damper receiving part 23 has the outer shape that is formed in the shape of a circle along the inner circumference of the cylindrical part 21 of the exhaust adapter 5 a, the exhaust adapter 5 a provided with the backflow prevention structure 18 a can be formed in the cylindrical part 21 having the same width as the exhaust pipe 4 a. The opening 26 through which the exhaust passes is formed in a shape of a circle with the center C1 eccentric from the center C0 of the circular damper receiving part 23, or formed in a partial circular shape having a part of this circle. The support shaft 24 of the exhaust damper plate 22 that opens and closes the opening 26 and the bearing part 25 thereof can be accommodated in the cylindrical part 21 while increasing the opening area by the eccentric circular shape or partially circular shape of the opening 26.

By making the opening 26 eccentric with respect to the damper receiving part 23, the wide part 23 a is formed in the damper receiving part 23, and the bearing part 25 is provided in the wide part 23 a. Therefore, since the bearing part 25 of the support shaft 24 that rotatably supports the exhaust damper plate 22 is provided in the wide part 23 a outside the opening 26, the exhaust adapter 5 a having a constant width may be formed without expanding the diameter of the cylindrical part 21. Therefore, when the exhaust adapter 5 a is covered with the heat insulating material, it can be easily covered because there are no parts having different widths.

In addition, a person skilled in the art can carry out the embodiments in forms in which various modifications are added to the above embodiments without departing from the spirit of the disclosure, and the disclosure includes such modified embodiments. 

What is claimed is:
 1. An exhaust adapter comprising: a cylindrical part for connecting an exhaust pipe of a combustion device to a collective exhaust duct for collecting and discharging exhaust of a plurality of the combustion devices; and a backflow prevention structure for preventing backflow of the exhaust from the collective exhaust duct side to the exhaust pipe side, wherein the backflow prevention structure comprises: a damper receiving part formed with an opening through which the exhaust from the exhaust pipe passes; an exhaust damper plate that opens the opening by pressure of the exhaust from the exhaust pipe and closes the opening by its own weight when there is no exhaust from the exhaust pipe; a support shaft that rotatably supports the exhaust damper plate; and a bearing part that supports the support shaft, wherein the exhaust damper plate comprises a pair of shaft hole parts for inserting the support shaft, and the pair of shaft hole parts is formed in a long hole shape that is long in a vertical direction with respect to the support shaft when the exhaust damper plate is in a posture in which the opening is closed.
 2. The exhaust adapter according to claim 1, wherein the cylindrical part is formed to have a width equal to a width of the exhaust pipe, the damper receiving part has an outer shape that is formed in a circular shape along an inner circumference of the cylindrical part, and the opening is formed in a shape of a circle with a center eccentric from a center of the circular damper receiving part, or formed in a partial circular shape having a part of this circle.
 3. The exhaust adapter according to claim 2, wherein the bearing part is provided in a wide part of the damper receiving part formed by making the opening eccentric. 